From the back cover:
More than a book...
The adventure novel you play as well as read! A role-playing fantasy with complete instructions for solo play, or for use with the most advanced role-playing games.
There were 4 books in this series, which was advertised on the front cover as "Suitable for use with Advanced Dungeons & Dragons(tm)* and other role-playing games - *Advanced Dungeons & Dragons is a trademark of TSR Hobbies, Inc. Use of this trademark is NOT sanctioned by the holder" It uses a variation on the AD&D system, using the same statistics, but rolling 3d6 for combat and risk resolution, and having only a couple of basic statistics for opponents, which unfortunately makes it unusable for AD&D as anything other than a story seed.
They provide a pre-generated character and have basic rules for creating your own but the book is written in the third person, using the provided character's name constantly and using his abilities, making it very difficult to use your own character. The story is a bit linear, a lot of the choices and challenges only serving to make the character lose resources. Only a few actually lead to death, and there is only one successful end.